Process of making pure oxid of tin.



, uNrTE STATES PATENT orFIon GUSTAV SPITZ, OF BRll'NN, AUSTRIA-HUNGARY, ASSIGNOR TO GOLDSCHMIDT DETIN- NING COMPANY, OF NEW YQRK, N. Y,, A CORPORATION OF NEW JERSEY.

' PROCESS OF MAKING PURE OXID F TIN.

No Drawing.

' To all whom it may concern:

'Be it known that I, GUSTAV Srrrz, sub ect of the Emperor of Austria-Hungary, and resident of Briinn, in the Empire of Austria-Hungary, have invented a new and useful lrocessof Making PureOxid of Tin, of \vhichthe following is an exact specification.

The present invention relates to a process of making pure oxid of tin from ti 'n containing or holding materials of any k nd, as.

' acid, but the color of this-oxid was yellow and not white.

for instance, for enamels.

According to the present invention it is possible to obtain a pure oxid of tin, with thelosses reduced to a minimum and practically negligible.

The rocess consists inplacing the tincontainmg or retaining materials, for instance, tin-plate Waste of any kind, in a closed vessel and heating them with alkaline solutions, for instance 0t caustic soda, under high'pressure and with the addition of an oxydizing materiahwhereby all the tin dismany technical purposes, as, for, instance,-

solves as stannate of sodium, the zinc as zincate and the lead as plumbate of sodium, while the impurities remain undis'solved and sink to the bottom. From the solution of stannate of sodium thus obtained, the insoluble parts are removed andthe lead is; precipitated by chemical methods, for in-, .stance by tin, and the zinc by sulfid of sodiumfor instance. The solution of stannate of sodium, from u'hich'the settled foreign metals have been separated, is further treated with carbonic acid, boric' acid or other acids or acid salts. Thusan'oxid of tin is obtained which shows a clear white color but which still contains a small amount from two to three per. cent.) of alkali These last -traces of alkali cannot be removed bywashing with Water, they adhere to the product and thus render it useless for for the manufacture of enamel. By numerous'experinients I have, found that the alkali is entirely removed by calcining the end Specification of Letters Patent.

'cining, which will so that'it could not be used,-

I of tin after it has been subjected to a Washing process, then grinding it if necessary,

then washing it with a dilute acid or with a solution of a salt of ammonium, and finally drying 1t. lVhen using nitric acid, the last traces of salts of lead and zinc, and even of salt of copper, maybe removed by washing. To remove the last traces of alkali it is Patented Dec. 1,1914. application filed November 6, 190a Serial No. 526,605.

necessary to calcine the-oxid of tin pre-.

viously. Grinding is only necessary when the OXld of tin has become hard by the cal- I be the case, if alkali is stillpresent- In order to prope'rly calcine the oxid of tin, it is necessary that it be heated to a high temperature, a red-white heat. It will not be sufiicient to slightly heat the product for the mere purpose of drying, but it must be heated up to 'a degree of temperature, as stated, corresponding to red-White heat.

manufacture of enamels must have the following qualities: It must be in a veryfinely 7 1 Oxid of tin which is to be employed in the, 1

divided state, amorphous, free from alkali' i and Water and of a pure white color. In

orderto obtain such a product, it is necessary to add to the solution of stannate of sodium the precipitatingmedium in such, a

manner that the oxid of tin has no time tobecome crystal-line, that is to say, the pre cipitating medium must be added so quickly andin such a quantitythat the oxid of tin does not separate gradually but all at once.

For this purpose it is best not to introduce gaseous carbonic acid into the boiling solution, as isusually -done,but preferably to introduce solid bicarbonate, and simultane ously to agitate the fluid.- It is advantageous if there are present intheliquid the various organic substances comprised in the waste materials and especially organic substances contained-in old cans-orboxes, for if such substances are present the separation of the oxid of tin in a'finely divided state is facilitated. It is only possible to use an aqueous solution of bicarbonate ofsoda as precipitating medium, if the solution is introducedunder a certain pressure, as' otherwise an aqueous solution ofbicarbonate of soda will become decomposed before boiling. In' this case theisolution ofstannate of sodium, from latter vessel a solution of bicarbonate of which the foreign metals, etc., have been re soda has been prepared by introducing carbonic acid under pressure into a solution of carbonate of sodium of say 40 degrees centigrade, while agitating the fluid. The solution of bicarbonate of soda thus prepared is underfia pressure of say about 4: atmospheres while the stannate solution is .under a pressure of say about 2 atmospheres. The stannate solution, under the pressure of 2 atmospheres, is heated up to 125 degrees Centigrade, after which the solution of bicarbonate of soda is admitted, being under a pressure of 1 atmospheres and thetemperature having been raised to say from 50 to 60 degrees centigrade by the absorption of carbonic acid. Oxid of tin is immediately precipitated in a finely divided amorphous state which renders it useful for enameling purposes. Naturally it is possi- 3 ble to similarly obtainv oxid of tin from any stannate solution, as, for instance, from those solutions whichare obtained in the electrolytic process of treating tin plate scraps in an alkaline bath.

According to the present process a perfectly white, finely divided powder of oxid of tin (99.5 to 99.9 per cent. SnO may be obtained. In order to remove traces of silica which may have entered the oxid of tin from 30 the material treated, it may be advantageous to wash with hydrofluoric acid or solutions of fiuorid of ammonium. As an example, oxid of tin is taken which, after having been dried'and calcined still contains about 3 35 per cent. of Na O in form of basic salts. For neutralizing this small percentage of Na,(), about 12 per cent. of marketable nitric acid would be required, but as other deleterious bodies may be present in the oxid of tin as, for instance, oxid of zinc and oxid 0% lead, which also are soluble in nitric acid, it is necessary to have an excess of nitric acid in proportion to the amount of these bodies, that is to say, for instance, 20 kilo grams or more of nitric acid may be emlo *ed with 100 kilograms of the above n The solution is boiled with fresh steam, and the precipitate is filtered oil, washed in the manner described and dried.

In my U. S. applications Ser. Nos. 526,603, and 526,604, I have described and claimed matters similar to those set forth in this application, and do not wish to be understood as here claiming the subject matters of said i Serial Nos.

What I claim is:

1. The process of producing pure tin oxid in the most amorphous condition possible, from stannate solutions, which consists in precipitating the tin oxid and calciningit unmixed with acid;

2. The process of producing pure tin oxid in the most amorphous condition possible, from stannate solutions, which consists in precipitating the tin oxid, washing the preniiaaa'r cipitate with water and calcining it unmixed with acid.

3. Theprocess-of producing pure tin oxid in the most amorphous condition possible, from stannate solutions, which consists in precipitating the tin oxid, washing the precipitate with water, calcining it unmixed with acid, and then washing said calcined precipitate.

4. The process of producing pure tin oxid in the most amorphous condition possible,

6. The step in the process of producing pure tin oxid in the most amorphous condi-"- tion possible from a stannate solution, which consists in treating said solution with a solution of alkali bicarbonate under pressure.

7. The step in the process of producing pure tin oxid in the most amorphous condition possible from a stannate solution, which consists in treating said solution with a solution of alkali bicarbonate under pres sure while agitating the solution.

8. In the process of producing pure tin oxid in the most amorphous condition possible from a stannate solution, treating said solut1on under pressure with a solution of alkali bicarbonate under a higher pressure while agitating the solution.

9: The process of producing pure tin oxid 1n the most amorphous condition possible from a stannate solution,ewhich consists in precipitating the tin oxid, by means of a solution of alkali bicarbonate under pres sure, and then calcining the precipitate.

10. The process of producing pure tin oxid in the most amorphous condition possible fromv a stannate solution, which con-- sists in precipitating the tin oxid by means of a solution of alkali bicarbonate under pressure'while agitating the solution, and then calcining the precipitate.

.11. The process of producing pure tin oxid in the most amorphous condition possible from a stannate solution, which consists in precipitating the tin oxid by means of a solution of alkali bicarbonate under pressure while agitating-the solution, then washing the precipitate with water, and calcining it unmixed with acid.

12. The process of producing pure tin oxid in the most amorphous condition possible, from stannate solutions, which consists in. precipitating the tin oxid by means of a solution of alkaline bicarbonate which has been separately prepared by introducing carbonic acid into a solution of carbonate of alkali under pressure, while agitating the fluid, then washing the precipitate with' water and calcining it.

13. The process of producing pure tin oXid in'the most amorphous condition possible, from stannate solutions, which consists in precipitating the tin oxid by means of a solution of alkali bicarbonate under pressure, while \agitating the fluid, then washing the precipitate with water, calcining it unmixed with acid, and then washing said calcined precipitate.

14. The process of vproducing pure tin oxid in the most amorphous condition possible from stannate solutions, which consists in precipitating'the tin oxid, washing the precipitate with water, calcining it at a red white heat unmixed with acid, and then washing said calcined precipitate.

15. The process of producing pure tin oxid in the most amorphous condition possible, from stannate solutions, which consists in precipitating the tin oxid by means of a solution of alkali bicarbonate under pressure, while agitating the fluid, then washing the precipitate with water, calcin- 0 ing it 'ata red-white temperature unmixed with acid, and then washing the calcined precipitate.

16. The process of producing pure and clear white amorphous tin oxid from a stannate solution, which consists in precipitating tin oxid, and converting the impurities in said precipitate into readily removable form. 17. Theprocess of producing pure and clear white amorphous tin oxid from an impure stannate solution, which consists in removing other metals that contaminate it,

- then precipitating the tin oxid, and then separating the remaining impurities from said precipitate.

18. The process of producing pure'and clear White amorphous tin oxid from a solution of an alkaline stannate, which consists in treating said solution to precipitate the tin oxid, and then separating the alkali from said precipitate.

19. The process of producing pure and clear white amorphous tin oxid from a solution of an alkaline stannate, which consists in treating said solution to precipitate the 'tin oxid, washing said precipitate to remove the major portion of the alkali, and then subjecting said precipitate to treatment suitable for-converting the residual alkali into readily removable form.

20. The'process of producing pure and clear white amorphous tin oXid from an impure solution of an alkaline stannate, which consists in removing from said solution other metals that contaminate it, then treating said ver-ting the alkali in said solution to precipitate the tin oxid, and then converting the alkali in said precipitate into readily removable form.

21. The process of producing pure and clear white amorphous tin oxid from a solution ofan alkaline stannate containing metallic and organic. impurities, which consists in removing from said solution other metals that contaminate it, then treating said solution to precipitate the tin oxid, and then separating the organic impurities and comprecipitate into readily removable form. r

22. The process of producing pure and clear white amorphous tin oxid from a solution of an. alkaline stannate containing v metallic and organic impurities, which consists in removing from said solution other metals that contaminate it, then treating said solution to precipitate the tin oxid, call tionof an alkaline stannate containing metallie and organicimpurities, which consists in removing from said solution other metals that contaminate it, then treating said solution to precipitate the tin oxid, and then separating the organic impurities and con- 1 5 verting the alkali in said precipitate into readily removable form.

25. The process of producing pure and, clear white amorphous tin oxid from analkaline stannate solution, which consists in 1 suddenly subjecting said solution to the action of a reagent suitable forprecipitating the tin oxid in the most amorphous condition possible, and then converting the alkali in said precipitate into readily removable 1 5' form.

26. The process of producing pure and clear white amorphous tin oxid from a solution of an alkaline stannate containing metallic and organic impurities, which consists i in removing from said solution other metals that contaminate it, then suddenly subjecting said solution to the action of a reagent suitable for precipitating the tin'oxid in the most amorphous condition possible, and 25 "then separating the organic impurities and converting the alkali in said precipitate into readily removable form. I 27. The process of producing pure amorphous tin oxid from a stannate solution con- 13o phous tin oxid' from tin-scrap containing oranic impurities, which consists in subjectmg said material to the action of a suitable detinning solution, removing from the resulting stannate solution other metals that contaminate it, precipitating the tin oxid from the resulting stannate solution contain-' ing organic impurities, and calcining said precipitate unmixed with acid.

29. The process of producing pure amorphous tin oxid from tin-scrap containing organic impurities which consists in sub ecting said material to the action of a suitable detinning solution, removing from the resulting stannate'solution other metals that contaminate it, precipitating the tin oxid sub stantiallyv instantaneously from the resulting stannate solution containing organic impurities, and calcining said precipitate unmixed with acid.

30. The process ofproducing ure amorphous tin oxid from a stannate so ution 'containing metallic and organic impurities, which consists iniremoving from said solution other'me'tals that contaminate it, precipitating tin'oxid from said solution containing organic impurities, and calcining said precipitate unmixed with acid.

31. The process of producing pure amorphous tin oxid from a stannate solution containing metallic and organic impurities, which consists in removing from said solution other metals that contaminate it, precipitating tin oxid from said solution contaming organic impurities, calcining said precipitate unmixed with acid, and washmg said calcined precipitate with acid.

The process of producing pure and clear white amorphous tin oxid from an alkaline stannate solution containing organic impurities, which consists in precipitating the tin oxid from said solution, and then separating the organic impurities and alkali from said precipitate.

33. The proccs of producing pure and clear white amporhous tin oxid from a tincontaining material, which consists in subjecting said material to the action of an alkaline solution containing an oxidizing material removing from the resulting stannate solution other metals that contaminate i it, precipitating the tin oxid from said stanarrest? ing from the resulting stannate solution other metals that contaminate it, precipitating the tin oxid from said stannate solution, and calcining said precipitate unmixed with acid. s

35. The process of producing pure amorphous tin oxid from a tin'containing material, which consists in subjecting said material at high pressure to the action of an alkaline solution, removing from the resulting stannate solution other metals that contaminate it, precipitating the tin oxid from said stannate solution, and converting the alkali in said precipitate into readily removable form.

36. The process of producing pure amor: phous tin'oxid from a tin-containing material, which consists in subjecting said material at high pressure to the action of an alkaline solution, removing from the resulting stannate solution other metals that con.- taminate-it, precipitating the tin oxid from said stannate solution, and calcining said precipitate unmixed with acid.

37 The process of producing pure amorphous tin oxid from a stannate solution, which consists in precipitating the tin oxid from said solution, 'calcining said precipitate unmixed with acid, grinding said calcined precipitate, and then washing said precipitate.

38. The process of producing pure amorphous tin oxid from a stannate solution containing substantially no metallic contaminations, which consists in precipitating the tin oxid substantially instantaneously from said solution, and calcining said precipitate unmixed with acid.

39. The process of producing pure amorphous tin oxid from a stannate solution, which consistsin precipitating the tin oxid from said solution, calcining said precipitate unmixed with acid, and washing said precipitate with dilute acid.

40. The step in the process of obtaining pureand clear white amporhous tin oxid,

which consists in separating the alkali from a precipitated amorphous oXid of tin-containing alkali.

41. The step in the process of producing pure and clear white amorphous tin oxid,

which consists in converting into readily removable form the alkali in a precipitated oxid of tin containing alkali.

4:2. The step in the process of obtaining pure and clear white amorphous tin oxid, which consists in calcining unmixed with acid, a precipitated amorphous oxid of tin containing alkali.

43. In the process of producing pure and clear white tin oxid, washing a precipitated oxid of tincontaining alkali, and then convertin into readily removable form the alkali in said precipitate.

44. In the process of producing pure tin oxid, Washing a precipitated oxid of tin containing alkali, calcining said precipitate unmixed with acid, and washing said calcined precipitate.

$5. In the process of producing pure tin oxid, Washing a precipitated oxid of tin containing alkali, calcining said precipitate unmixed with acid, and washing said calcinedprecipitate with acid.

46. In the process of producing pure and clear white tin oxid, separating the organic impurities from a precipitated oxid of tin containing alkali and organic and metallic impurities, and then separating residual alkali and metallic impurities from said precipitate.

$7. In the process of producing pure tin oxid, calcining, unmixed with acid, a precipitated oxid of tin containing alkali, and then Washing the calcined precipitate.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

GUSTAV SPITZ.

Witnesses AUGUST FUGGER, ALEXANDER WVEINGARTNER.

Copies of this patent may be obtained for flve cents each, by addressing the Commissioner of Patents.

Washington, D. 0. 

